They help users understand how the category relates to other categories.

They help users jump up to higher levels on the hierarchy. In the example above, you can jump all the way from Category:Contraltos to Category:Performing arts with one click. Without the classification it would take five clicks.

The easiest way to create a classification is to use a template if there is one that is appropriate. See the template section below. If there is no template that will work you can add a classification by manually editing a category to insert links. The classification for Contraltos was created with this text:

The classification should be centered on the page (this is what the surrounding <div...>...</div> does).

The classification goes at the top of the category page, before any {{Cat main}} and other templates and content.

"Classification:" should be bold.

Prefix a colon, as in [[:Category..., to make a category appear as a link. If it doesn't appear when you preview, you forgot the colon.

Remove redundant words from categories (for example: "Singers" instead of "Opera singers" in this example), where this will not result in confusion; the first word of the link shown should be capitalized.

The last category, the one being edited, should also be bold.

Important: Decide where to begin the hierarchy. There is a natural starting place for most hierarchies. You don't have to go all the way to Category:Fundamental categories. Pick a high level that is not distantly related to the category. Often, the high level will be at the bottom of several different higher level hierarchies. This is a good indicator of a natural starting place.

Multiple classifications are possible. List the second one on the next line. Instead beginning the line with '''Classification:''' type ''also:''. You don't have to add a classification for every possible hierarchy. Sometimes, the hierarchy is just a link between different hierarchies.

For example: Category:African American actors is part of the hierarchy under Category:African Americans. It is also a subcategory of Category:American actors. It is one of just a few sub-groupings under American actors (not all ethnicities are subcategories of American actors), and the entries are duplicated in both categories. This is because they are in effect just related categories. Instead of showing that connection as a classification, it might make more sense to just put a link such as See also: Category:American actors.

Another option, when a category is a subcategory of multiple parent categories of the same level, all themselves subcategories of a single "grandparent", is to use commas and "and" to show them all in the classification, in shortened form. The serial comma is recommended, for clarity. Example:

There are several templates to help classify categories (and more on the way). It is much easier to use a template than to set it up manually. Here are the templates that currently exist. See the discussion page for the template for examples of how to use them.